Alternator "excite" wire not kicking alternator in

[bigdan002001]

Ok, I replaced pretty much all the electrical stuff on the front of the motor of my 97 ranger with a 4.0L engine back last year. New gator back belt, new idler pulley, new alternator, new tensioner, new cables, new battery. Truck ran fine up until the other night when the battery light kicked on in the dash and the new alternator started making a bad noise....so figured bearing going down, which it was cause it was noisy and shaft had a lot of endplay in it. Well, I go to advanced and pick up a new one under lifetime warranty and bring it home. I have a new optima red top battery on it as well with new cables and connectors. I hooked up battery to a charger so it would charge up the battery before running the new alternator cause too much strain can overheat and ruin a new alternator. Well after battery is fully charged, I start the truck and the noise is gone...sounds good, but the light is still on in the dash and the needle is clear down to L on the dash....so the alternator is not doing anything. I took it off and went to advance to have them test the brand new alternator and it outputs just fine and they told me the exiite wire (the little white/black stripe wire) isn't getting a signal to kick the alternator on. Truck starts and runs just fine, but runs totally off the battery. So that would rule out the fusible link wouldn't it? I checked number 15 fuse in the dash which is the 7.5A fuse for the alternator and it is fine as well. There is another fuse somewhere based on the wiring diagram in my haynes manual, but I am assuming it is under the hood in the power distribution box. I need to find that one and check it but don't know which one it is? Also could the resistor in the dash that runs the battery light be burnt into and not letting the circuit continue out to the alternator which would mean a new dash cluster? I am stumped on this one...also where is the fusible link located as well, so I can double check to make sure it's not that, but didn't think the starter would engage if it were burnt into. Thanks,

Dan

 

[Bulldog99]

'Excite' wire problem - Fixed?

Hey Dan,

Just wondered if you ever found out what was wrong with your charging system?

I have a similar problem on my '99 and after much searching, this is a fairly common failure on these vehicles but no one ever seems to post what the result was.

So what was the fix on yours?

Thanks,
Steve